Coating or plastic



coAi'liiooa PLASTIC.

- aMM D AT S I UV ilillttirdtsw HENRY w. MERRITT, F BOSTON, MASsAoHUSE'rTs, ASSIGNOR TO WILLIAM- H. IRELAND, OF SAME PLACE.

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' SPECIFICATION forming part of Letters Patent No. 341,157, dated May 4-, 1886.

Application filed January 15, 1888. Serial No. 188,657. (No ape To all whom it may concern:

Be it known that I, HENRY W. MERRITT, of

Boston, county of Suffolk, and State of Massachusetts, have invented an Improvement in 5 Plastic Go'mpoundspf which the following description is a specification. r A

This invention is an improvement upon that which has been secured to me by Letters Pat! ent of the United States No. 322,391, granted to July 14, 1885; and its object is to secure a new and more economic mode and means of obtaining a Lstic compound which, when exposed to the air, willset and become extremely hard.

"Th the practice of my ibrmer invention I I 5 preferably employed as ingredients of theplastii: compound to be formed a hi hl silicious si icate of ma 'nesia called ashestlne in a pulverized condition, uartz-sand and caustic soda or caustic ota' w1 1 wa or to dissolve the alkall and give plasticity to the mass when thes'e'jp'grgdients were thoroughly incorposmall proportion of alkaline silicate to make I the plastic mass more a esi ave dis- 2 5 covered, however, that when' such a highly silicious solid silicate as asbestine'is combined with a highly basic alkaline silicate in suflicient proportion to bring about extensive chemical reaction between them there results a compound which hardens into a coherent solimumlmfiholds and binds any ty-two per cent. of soda Na 0 to a out vent-e1 iO the forum a in t is instance being represented substantially by Na,0 (SiO,) 4. These ingrelents mix oge er W1 1 om eighteen to twenty-two pounds of water and the whole will then fill a pail of ordinary size. \Vith this I incorporate double its bulk or about two pailfuls of sand which, if dry, would weigh from one hundred and-ten to one hundred and fifteenpounds. This mass, when thoroughly intermixed, makes a plaster of proper consistency to apply with a trowel in the usual manner. t

The plastic compound soformed gradually hardens on exposure to the air, and finally becomes very stone-like in its character.

The chemica relatlons o elngret tents of this compound, as far as I have been able to ascertain them, may be stated as follows: Asbestine is a silicate of magnesia in which the proportion of silicic acid to the magnesicba'se combined therewith is high, while in an alkaline silicate existing in the form of an aqueous solution the proportion of silicic acid to the alkaline base is low. considered with reference to their relative chemical quantivalence, so that when the asbstine -which is predominantly acid in characterandthe alkalinesilicatewhich is redominantl Basic in character-are brought together, the one in fine sand or o l r uted mineral moo orae 1ntO1t\l,\'| sate. I am thus enabled to dis ense with h xed caustic alkali as a primary ingredient oi the plas- 10 compound, and to employ the sand chiefly or the purpose of extending the hulk'of the ass. g In this new compound I use silicate of soda 0 or silicate of )otash in whie 1 e g, a we base 1s so igepg nderaut as to render such sillcate soluble inwater. ,I have also found that a double silicate of soda and potash is more powerful in Us 0 elmca reaction upon the 3g; bestine and s and than asimple silicate of either soda or potashalone. In order to make a good plaster for walls, I

7 0 take fourteen pounds of pulverized asbestine and from seven to ten pounds of alkaline silipowder and the other in Solution, a chemical union takes place between the silicic acid of its silicic acid and the base of the soluble alkaline silicate, so as to produce further chemmass; but such reaction would presumably be "l5o cate in HCIIGOIL lu having a density of q 0 'fiout etliBaum and containing about twen- WQtfi- I hts-QlghtwQhD confined substantially to the exposed surfaces the solid magnesia SllHL QLQ and the alkali of' eimens.) J

ic'al union between the constituents of the mo of the sand, and this result, whatever itmay be, is only collateral to the production of the principal binding compound.

Variations may be made within considerably wide limits in the proportions of the ingredients which constitute my new plastic compound herein described; but considerations of economy will prevent much departure from the relative proportions already stated. Thus,

to if the uantit of asbestine used be in excess of that needed to iurn'islfsilicic acid enough ,to satisfy the aflinity of the base of the solusilicateusedbe igggcess of that needed to "satisfy the aflinity of the silicic acid present in the asbestine and sand, then such excess, if not too great, will harden and be held within 7 the mass of the binding compound formed by the chemical union which does take place between the ingredients. It will be seen that the highly silicious magnesic silicate and the highly basic alkaline silicate are the essntr ons 1 uents of the plastic compound, since the resultant stone-like product is due chiefly to their chem- 3 5 ical combination, and that thesand introduced along with them is used mainly for the purpose of economy in extending the bulk of plastic material wherein it is held and bound by the solid compound formed by the chemical 4o union of the active ingredients. Consequent- -ly the quantity of sand fgizother equivalent comminuted minera w m may be used to extend the bfiikbl' the plastic compound can be made to vary from nothing up to the practical limflz within which its artiles will 1- e w ,0 can moose 1n the ass of the binding commmsmm from the chemical union of the magnesic and alkaline silicates.

It is important for the most efficient and centrated as is consistent with obtaining K the plastic compound.

I claim- 7 1. A plasticcompound containing as ingredients a highly silicious silicate of magnesia in a pulverized state and ahighly basic alkaline silicate in aqueous solution, each in such proportion as to satisfy substantially the mutual affinity of thepredominant silicic acid of the one and the predominant alkaline base of the other, and to form a resultant chemical compound which on exposure to the air will harden and bind into its coherent mass such proportion of sand or other comrninuted mineral as may be incorporated therewith, substantially as described.

2. A plastic compound consisting of ahighly silicious silicate of magnesia in a pulverized condition, a highly basic silicate of soda and potash in aqueous solution, and comminuted silica, the whole being intermixed and incorporated, substantially as described.

3. A. plastic compound containing as ingredients pulverized asbestine, ahighly basic alkaline silicate in sufificient proportion to satisfy substantially the affinity of the predominant silicic acid in the asbestine, and a proportion of sand not exceeding in amount what can practically be bound by the coherent mass resulting from the chemical union of the asbestine and alkaline silicate, the whole being intermixed and incorporated, substantially as described. I

In .testimony whereof I have signed my thorough incorporation of the ingredients of name to this specification in the presence of go two subscribing witnesses.

' HENRY w. MERRITT.

Vitnesses: I

G. W. GREGORY, C. M. Conn. 

